The proposed merger of two high-risk COPD groups within the GOLD stratification system could lead to over-treatment in clinical practice, researchers warn.

According to the research team, combining the Global Initiative on Obstructive Lung Diseases categories C and D into E should be reconsidered as their study findings revealed a significant difference in symptom scores in patients who would have previously been stratified into groups C and D.

The study was based on data from 1,529 users of the myCOPD mobile app. Researchers quantified symptoms for patients in each GOLD group using COPD Assessment Tests (CAT) and exacerbation rate over 12 months post-classification.

Results showed that CAT scores for app users initially classified into GOLD C and GOLD D categories remained significantly different after 12 months.

Also, those in the C category had a lower exacerbation rate than those in the D group during the 12 months after classification, while those in group D had a higher cumulative total of exacerbation days than all other groups.

As symptoms remained lower in the GOLD C group one year after stratification, just one-quarter (25.2%) would have been escalated at a 12-month review, while 38.5% would have been de-escalated to GOLD groups A or B.

“Based on this evidence, it is unlikely that users in GOLD C and D would converge after 12 months,” the team wrote in their paper published in the International Journal of Chronic Obstructive Pulmonary Disease,

The findings “demonstrate that symptoms (CAT scores) are critical for stratifying disease progression regarding symptomology and future exacerbation risk.

“GOLD E will contain a variety of disease acuities, which could potentially lead to a loss of clarity and over-treatment in clinical practice,” they warned.

Possibly misleading?

However, UK consultant physician Professor David Halpin, a member of the Board of Directors of the GOLD and the GOLD Science Committee, told the limbic that the A, B and E categories are purely intended to help clinicians determine appropriate initial therapy and are not for long-term prognosis.

Also, regarding the study’s methodology, he suggested that categorising patients who have already been treated could be misleading as the GOLD classification system should only be used for those who are naive to treatment.

Rejecting the call for a re-think on the merger of groups C and D, he said: “It’s very interesting that the work showed that symptoms and the CAT score are a good predictor of long-term outcomes, and clinicians should bear that in mind. However, it’s probably not so relevant to determining initial therapy”.

In response, the study authors, led by Christopher Duckworth, Honorary Research Engineer at University Hospital Southampton NHS Foundation Trust, told the limbic: “All patients with COPD can benefit from a better understanding of their prognosis to help guide treatment; we would support the use of digital tools very early on in the clinical pathway which will hopefully guide initial decisions and drive an evolution of clinical strategies to become more data-driven.”